--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LED driver for Richtek RT8515 flash/torch white LEDs
+ * found on some Samsung mobile phones.
+ *
+ * This is a 1.5A Boost dual channel driver produced around 2011.
+ *
+ * The component lacks a datasheet, but in the schematic picture
+ * from the LG P970 service manual you can see the connections
+ * from the RT8515 to the LED, with two resistors connected
+ * from the pins "RFS" and "RTS" to ground.
+ *
+ * On the LG P970:
+ * RFS (resistance flash setting?) is 20 kOhm
+ * RTS (resistance torch setting?) is 39 kOhm
+ *
+ * Some sleuthing finds us the RT9387A which we have a datasheet for:
+ * https://static5.arrow.com/pdfs/2014/7/27/8/21/12/794/rtt_/manual/94download_ds.jspprt9387a.jspprt9387a.pdf
+ * This apparently works the same way so in theory this driver
+ * should cover RT9387A as well. This has not been tested, please
+ * update the compatibles if you add RT9387A support.
+ *
+ * Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/led-class-flash.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+
+#include <media/v4l2-flash-led-class.h>
+
+/* We can provide 15-700 mA out to the LED */
+#define RT8515_MIN_IOUT_MA 15
+#define RT8515_MAX_IOUT_MA 700
+/* The maximum intensity is 1-16 for flash and 1-100 for torch */
+#define RT8515_FLASH_MAX 16
+#define RT8515_TORCH_MAX 100
+
+#define RT8515_TIMEOUT_US 250000U
+#define RT8515_MAX_TIMEOUT_US 300000U
+
+struct rt8515 {
+ struct led_classdev_flash fled;
+ struct device *dev;
+ struct v4l2_flash *v4l2_flash;
+ struct mutex lock;
+ struct regulator *reg;
+ struct gpio_desc *enable_torch;
+ struct gpio_desc *enable_flash;
+ struct timer_list powerdown_timer;
+ u32 max_timeout; /* Flash max timeout */
+ int flash_max_intensity;
+ int torch_max_intensity;
+};
+
+static struct rt8515 *to_rt8515(struct led_classdev_flash *fled)
+{
+ return container_of(fled, struct rt8515, fled);
+}
+
+static void rt8515_gpio_led_off(struct rt8515 *rt)
+{
+ gpiod_set_value(rt->enable_flash, 0);
+ gpiod_set_value(rt->enable_torch, 0);
+}
+
+static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod,
+ int brightness)
+{
+ int i;
+
+ /*
+ * Toggling a GPIO line with a small delay increases the
+ * brightness one step at a time.
+ */
+ for (i = 0; i < brightness; i++) {
+ gpiod_set_value(gpiod, 0);
+ udelay(1);
+ gpiod_set_value(gpiod, 1);
+ udelay(1);
+ }
+}
+
+/* This is setting the torch light level */
+static int rt8515_led_brightness_set(struct led_classdev *led,
+ enum led_brightness brightness)
+{
+ struct led_classdev_flash *fled = lcdev_to_flcdev(led);
+ struct rt8515 *rt = to_rt8515(fled);
+
+ mutex_lock(&rt->lock);
+
+ if (brightness == LED_OFF) {
+ /* Off */
+ rt8515_gpio_led_off(rt);
+ } else if (brightness < RT8515_TORCH_MAX) {
+ /* Step it up to movie mode brightness using the flash pin */
+ rt8515_gpio_brightness_commit(rt->enable_torch, brightness);
+ } else {
+ /* Max torch brightness requested */
+ gpiod_set_value(rt->enable_torch, 1);
+ }
+
+ mutex_unlock(&rt->lock);
+
+ return 0;
+}
+
+static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled,
+ bool state)
+{
+ struct rt8515 *rt = to_rt8515(fled);
+ struct led_flash_setting *timeout = &fled->timeout;
+ int brightness = rt->flash_max_intensity;
+
+ mutex_lock(&rt->lock);
+
+ if (state) {
+ /* Enable LED flash mode and set brightness */
+ rt8515_gpio_brightness_commit(rt->enable_flash, brightness);
+ /* Set timeout */
+ mod_timer(&rt->powerdown_timer,
+ jiffies + usecs_to_jiffies(timeout->val));
+ } else {
+ del_timer_sync(&rt->powerdown_timer);
+ /* Turn the LED off */
+ rt8515_gpio_led_off(rt);
+ }
+
+ fled->led_cdev.brightness = LED_OFF;
+ /* After this the torch LED will be disabled */
+
+ mutex_unlock(&rt->lock);
+
+ return 0;
+}
+
+static int rt8515_led_flash_strobe_get(struct led_classdev_flash *fled,
+ bool *state)
+{
+ struct rt8515 *rt = to_rt8515(fled);
+
+ *state = timer_pending(&rt->powerdown_timer);
+
+ return 0;
+}
+
+static int rt8515_led_flash_timeout_set(struct led_classdev_flash *fled,
+ u32 timeout)
+{
+ /* The timeout is stored in the led-class-flash core */
+ return 0;
+}
+
+static const struct led_flash_ops rt8515_flash_ops = {
+ .strobe_set = rt8515_led_flash_strobe_set,
+ .strobe_get = rt8515_led_flash_strobe_get,
+ .timeout_set = rt8515_led_flash_timeout_set,
+};
+
+static void rt8515_powerdown_timer(struct timer_list *t)
+{
+ struct rt8515 *rt = from_timer(rt, t, powerdown_timer);
+
+ /* Turn the LED off */
+ rt8515_gpio_led_off(rt);
+}
+
+static void rt8515_init_flash_timeout(struct rt8515 *rt)
+{
+ struct led_classdev_flash *fled = &rt->fled;
+ struct led_flash_setting *s;
+
+ /* Init flash timeout setting */
+ s = &fled->timeout;
+ s->min = 1;
+ s->max = rt->max_timeout;
+ s->step = 1;
+ /*
+ * Set default timeout to RT8515_TIMEOUT_US except if
+ * max_timeout from DT is lower.
+ */
+ s->val = min(rt->max_timeout, RT8515_TIMEOUT_US);
+}
+
+#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
+/* Configure the V2L2 flash subdevice */
+static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,
+ struct v4l2_flash_config *v4l2_sd_cfg)
+{
+ struct led_classdev *led = &rt->fled.led_cdev;
+ struct led_flash_setting *s;
+
+ strscpy(v4l2_sd_cfg->dev_name, led->dev->kobj.name,
+ sizeof(v4l2_sd_cfg->dev_name));
+
+ /*
+ * Init flash intensity setting: this is a linear scale
+ * capped from the device tree max intensity setting
+ * 1..flash_max_intensity
+ */
+ s = &v4l2_sd_cfg->intensity;
+ s->min = 1;
+ s->max = rt->flash_max_intensity;
+ s->step = 1;
+ s->val = s->max;
+}
+
+static void rt8515_v4l2_flash_release(struct rt8515 *rt)
+{
+ v4l2_flash_release(rt->v4l2_flash);
+}
+
+#else
+static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,
+ struct v4l2_flash_config *v4l2_sd_cfg)
+{
+}
+
+static void rt8515_v4l2_flash_release(struct rt8515 *rt)
+{
+}
+#endif
+
+static void rt8515_determine_max_intensity(struct rt8515 *rt,
+ struct fwnode_handle *led,
+ const char *resistance,
+ const char *max_ua_prop, int hw_max,
+ int *max_intensity_setting)
+{
+ u32 res = 0; /* Can't be 0 so 0 is undefined */
+ u32 ua;
+ u32 max_ma;
+ int max_intensity;
+ int ret;
+
+ fwnode_property_read_u32(rt->dev->fwnode, resistance, &res);
+ ret = fwnode_property_read_u32(led, max_ua_prop, &ua);
+
+ /* Missing info in DT, OK go with hardware maxima */
+ if (ret || res == 0) {
+ dev_err(rt->dev,
+ "either %s or %s missing from DT, using HW max\n",
+ resistance, max_ua_prop);
+ max_ma = RT8515_MAX_IOUT_MA;
+ max_intensity = hw_max;
+ goto out_assign_max;
+ }
+
+ /*
+ * Formula from the datasheet, this is the maximum current
+ * defined by the hardware.
+ */
+ max_ma = (5500 * 1000) / res;
+ /*
+ * Calculate max intensity (linear scaling)
+ * Formula is ((ua / 1000) / max_ma) * 100, then simplified
+ */
+ max_intensity = (ua / 10) / max_ma;
+
+ dev_info(rt->dev,
+ "current restricted from %u to %u mA, max intensity %d/100\n",
+ max_ma, (ua / 1000), max_intensity);
+
+out_assign_max:
+ dev_info(rt->dev, "max intensity %d/%d = %d mA\n",
+ max_intensity, hw_max, max_ma);
+ *max_intensity_setting = max_intensity;
+}
+
+static int rt8515_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct fwnode_handle *child;
+ struct rt8515 *rt;
+ struct led_classdev *led;
+ struct led_classdev_flash *fled;
+ struct led_init_data init_data = {};
+ struct v4l2_flash_config v4l2_sd_cfg = {};
+ int ret;
+
+ rt = devm_kzalloc(dev, sizeof(*rt), GFP_KERNEL);
+ if (!rt)
+ return -ENOMEM;
+
+ rt->dev = dev;
+ fled = &rt->fled;
+ led = &fled->led_cdev;
+
+ /* ENF - Enable Flash line */
+ rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW);
+ if (IS_ERR(rt->enable_flash))
+ return dev_err_probe(dev, PTR_ERR(rt->enable_flash),
+ "cannot get ENF (enable flash) GPIO\n");
+
+ /* ENT - Enable Torch line */
+ rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW);
+ if (IS_ERR(rt->enable_torch))
+ return dev_err_probe(dev, PTR_ERR(rt->enable_torch),
+ "cannot get ENT (enable torch) GPIO\n");
+
+ child = fwnode_get_next_available_child_node(dev->fwnode, NULL);
+ if (!child) {
+ dev_err(dev,
+ "No fwnode child node found for connected LED.\n");
+ return -EINVAL;
+ }
+ init_data.fwnode = child;
+
+ rt8515_determine_max_intensity(rt, child, "richtek,rfs-ohms",
+ "flash-max-microamp",
+ RT8515_FLASH_MAX,
+ &rt->flash_max_intensity);
+ rt8515_determine_max_intensity(rt, child, "richtek,rts-ohms",
+ "led-max-microamp",
+ RT8515_TORCH_MAX,
+ &rt->torch_max_intensity);
+
+ ret = fwnode_property_read_u32(child, "flash-max-timeout-us",
+ &rt->max_timeout);
+ if (ret) {
+ rt->max_timeout = RT8515_MAX_TIMEOUT_US;
+ dev_warn(dev,
+ "flash-max-timeout-us property missing\n");
+ }
+ timer_setup(&rt->powerdown_timer, rt8515_powerdown_timer, 0);
+ rt8515_init_flash_timeout(rt);
+
+ fled->ops = &rt8515_flash_ops;
+
+ led->max_brightness = rt->torch_max_intensity;
+ led->brightness_set_blocking = rt8515_led_brightness_set;
+ led->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
+
+ mutex_init(&rt->lock);
+
+ platform_set_drvdata(pdev, rt);
+
+ ret = devm_led_classdev_flash_register_ext(dev, fled, &init_data);
+ if (ret) {
+ dev_err(dev, "can't register LED %s\n", led->name);
+ mutex_destroy(&rt->lock);
+ return ret;
+ }
+
+ rt8515_init_v4l2_flash_config(rt, &v4l2_sd_cfg);
+
+ /* Create a V4L2 Flash device if V4L2 flash is enabled */
+ rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg);
+ if (IS_ERR(rt->v4l2_flash)) {
+ ret = PTR_ERR(rt->v4l2_flash);
+ dev_err(dev, "failed to register V4L2 flash device (%d)\n",
+ ret);
+ /*
+ * Continue without the V4L2 flash
+ * (we still have the classdev)
+ */
+ }
+
+ return 0;
+}
+
+static int rt8515_remove(struct platform_device *pdev)
+{
+ struct rt8515 *rt = platform_get_drvdata(pdev);
+
+ rt8515_v4l2_flash_release(rt);
+ del_timer_sync(&rt->powerdown_timer);
+ mutex_destroy(&rt->lock);
+
+ return 0;
+}
+
+static const struct of_device_id rt8515_match[] = {
+ { .compatible = "richtek,rt8515", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rt8515_match);
+
+static struct platform_driver rt8515_driver = {
+ .driver = {
+ .name = "rt8515",
+ .of_match_table = rt8515_match,
+ },
+ .probe = rt8515_probe,
+ .remove = rt8515_remove,
+};
+module_platform_driver(rt8515_driver);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("Richtek RT8515 LED driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff